implanting an adult rat with the single-channel epoch ... · implanting an adult rat with the...

Epoch ECG Systems- Available from BIOPAC

Implanting an Adult Rat with the Single-Channel Epoch Transmitter forRecording EEG

November 21, 2013


Recommended Surgical Tools

A. Scalpel handle

B. Scalpel blade (#15)

C. Fine scissors

D. Burr tool

E. Fine burr (FST #19007-09or equivalent)

F .4x Hemostats (curved)

G. Toothed forceps

H. Absorbent spears or cotton-tipped applicators

I. Needle drivers

J. Accelerant (Loctite 7452 orequivalent)

K. Cyanoacrylate (Loctite 4541or equivalent)

L. Suture (Vicryl 4-0)

M. Electrocautery unit


Sterilize Transmitter

Ethylene Oxide• Place transmitter in Tyvek pouch

• Gas for a complete Kill cycle

• Off-gas for at least 24 hours

Isopropyl Alcohol• Soak in 70% ethanol for 1 minute

• Rinse in sterile saline


Anesthesia

• Anesthetize animal andmaintain anesthesiaaccording to IACUC-approved protocol


Shave Scalp

• Shave the scalp of theanimal over the skull andremove excess hair


Fix Position in Stereotaxic frame

• Each ear bar tip must beproperly positioned inauditory meatus

• Do not excessively tightenear bars

• Make sure anesthesia nosecone is secure

• A heated water blanket orheating pad is used underthe animal to keep it warmduring surgery

• Periodically check depth ofanesthesia with cornealreflex, limb pinch, or pulseoximetery.


Protect the Animal’s Eyes

• Apply lubricant eyeointment to each eye

• A mixture of mineral oil(20%) and whitepetrolatum (80%)


Sterilize Incision Site

• Swab the scalp withalternating applicationsof 70% ethanol andbetadine.

• Start in the center of thescalp and makeincreasingly widerconcentric circles.


Scalp Incision

• Incision is made slightlybehind the eyes along themidline, approximately ¾”.

• Try to make a single cut,which results in betterhealing.


Exposing the Scalp

• Use hemostats to graspscalp.

• Gently pull scalp awayfrom midline at fourcorners.

• Look for anatomicallandmarks in the skullsuch as Bregma andLambda.


Clean and Dry the Skull

• Remove all periosteumfrom the exposed surfaceof the skull.

• Cauterize any bleedingsections of bone.

• Skull must be completelydry.


Drill two holes in the skull over desired electrode locations

• Recommend usingDremel-type tool with aburr-type drill bit

• Practice drilling burr holesin a block of wood beforeattempting in a rat.

• Holes should be biggerthan 300 μm in diameter.

• Burr sizes of 0.9 mmproduce clean holes.

• Alternatively, no holesneed to be drilled forstable EEG recordings.


Check Spacing

• EEG from each electrodeis subtractive (electrode 1– electrode 2).

• Holes can be within ahemisphere or betweenhemispheres.

• Alternatively, no holesneed to be drilled forstable EEG recordings.


Trim Electrode Leads

• Use surgical scissors totrim the electrodes to thedesired length.


Check Electrode

• Check the fit of thetransmitter and gently bendelectrodes to line up over theintended sites for burr holes.

• Trim excess electrode

length.


Drill Anchoring Screw Holes

• Create two additional burrholes outside of the footprintof the transmitter.


Insert Anchoring Screws

• Use sterile self-tappingwood screws.

• Use “0” x 1/8 inch 303stainless steel screws orequivalent.

• Insert screws with sterile“jewelers” screw driver.

• Screws should be snugwith the head of the screwand one or two threadsexposed.


Maintain a Dry Skull

• Be certain that the skull isdry before gluing thetransmitter to the skull.


Check Fit

• Check the fit of thetransmitter.

• Electrodes should guidethrough the holes in theskull.

• Transmitter should fitbetween the twoanchoring screws.


Apply Cyanoacrylate

• Liberally applycyanoacrylate on the baseof the transmitter aroundthe outside edge.

• Make sure to avoidcoating the electrodes


Apply Cyanoacrylate

• Cyanoacrylate will flow tothe center of thetransmitter when placedon the skull.


Apply to Skull

• Thoroughly dry skullbefore placing transmitterto ensure strong adhesivebond.

• Apply transmitter coatedwith cyanoacrylate to theskull.

• Take care to alignelectrodes withcorresponding burr holes.

• Try to avoid piercingmajor vascular structures.

• Hold the transmitter inplace for one minute.


Apply Accelerant

• Apply accelerant througha syringe around thecyanoacrylate at the baseof the implantedtransmitter.

• Use accelerant sparingly,taking care not to applyto adjacent tissue.

• Cyanoacrylate accelerantis useful to speed curingof adhesive, but is notnecessary.


Apply Additional Adhesive

• Apply additionalcyanoacrylate around thebase of the transmitter.

• Thoroughly cover bothanchoring screws.

• Push cyanoacrylate upthe sides of thetransmitter.


Apply Accelerant

• Apply accelerant througha syringe around thecyanoacrylate at the baseof the implantedtransmitter.

• Use accelerant sparingly,taking care not to apply toadjacent tissue.

• Wash away excessaccelerant with sterilesaline.


Suture Skin

• Suture the skin around thebase of the transmitter,but do not cover thetransmitter.

• Top of transmitter must beabove skin to efficientlytransmit neural signals.

• Skin should be reasonablytight around thetransmitter.


Remove Animal

• Remove animal fromstereotaxic frame andplace on heated blanketfor recovery.

• A triple antibiotic can beapplied to the sutures andaround the base of thetransmitter.

• Animals should be warmand mobile beforereturning to their homecage.


Recover Animal

• Once animal is active,moving around, andgrooming, it can bereturned to its home cage.


Care and Housing

• Recordings maycommence directly afteranimal has recoveredfrom surgery.

• Sutures may need to beremoved from the scalpafter one week.

• Check for signs ofnecrosis around thetransmitter and treatwhere needed.

implanting an adult rat with the single-channel epoch ... · implanting an adult rat with the...

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